Impact of tropical and extra tropical climate variability on Indian Ocean surface waves

Weller

et al. 2021

Sci Rep

The influence of increasing sea surface temperatures (SSTs), in response to greenhouse warming, on wave power (WP) remains uncertain. Here, seasonal relationships between SST anomalies and mean and extreme WP over the Indo-Pacific Ocean are examined. Overall, seasonal WP has significantly increased over much of the Pacific, Indian, and Southern Ocean by 1.21–3.10 kW/m dec−1 over 1979–2019. Contributions from wave characteristics, namely significant wave height (SWH) and peak wave period (PWP), to changes in WP show that SWH contributes most in extra-tropical regions, and PWP most in tropical regions. Further, seasonal relationships between SST anomalies and WP indicate that increases in WP are also seen during strong El Niño years in December–February, and in-phase combinations of El Niño and positive Indian Ocean Dipole (IOD) events during June–August and September–November. Results highlight both long-term increasing SSTs and climate variability roles for inducing large-scale seasonal WP changes throughout the Indo-Pacific.

Section: Resultsmentioning

confidence: 94%

Section: Resultsmentioning

confidence: 99%

Positive relationship between seasonal Indo-Pacific Ocean wave power and SST

Weller

et al. 2021

Sci Rep

“…In addition, significant impact of the IOD|ENSO on SWH is constrained to the eastern IO and BOB in JJA, with decreases in mean PWP. This indicates that whilst swells dominate the IO, wind seas (directly generated and strongly coupled to local winds) are also of importance in JJA during positive IOD events (Remya et al, 2020 where decreases in PWP occur over the majority of the PO (Fig. 3c).…”

Section: Iod Influencementioning

confidence: 97%

“…Overall, an increase in SWH and decrease in PWP over regions such as the BOB and the northwestern Australian coast in DJF are associated with the seasonal increase in small fetch winds (Remya et al 2020). In addition, significant impact of the IOD|ENSO on SWH is constrained to the eastern IO and BOB in JJA, with decreases in mean PWP.…”

Section: Iod Influencementioning

confidence: 99%

“…In MAM, ENSO reduces the PDO signals over the PO. In addition, seasonal SLP teleconnection patterns regressed against ENSO|IOD, IOD|ENSO, ENSO|IOD, and PDO|ENSO, exhibit a high and low pressure anomaly that in turn generates strong winds(Kumar et al 2016(Kumar et al , 2019Patra et al 2020;Remya et al, 2020;Yang and Oh 2018) and consequently enhances the wave parameters (i.e. Hs and Tp) in the respective localized regions.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Influence of Natural Climate Variability on Extreme Wave Power over Indo-Pacific Ocean Assessed using ERA5

Weller

et al. 2021

Preprint

In recent decades, wave power (WP) energy from the ocean is one of the cleanest renewable energy sources associated with oceanic warming. In Indo-Pacific Ocean, the WP is significantly influenced by natural climate variabilities, such as El Niño Southern Oscillation (ENSO), Indian Ocean Dipole (IOD) and Pacific Decadal Oscillation (PDO). In this study, the impact of major climate variability modes on seasonal extreme WP is examined over the period 1979–2019 using ERA5 reanalysis data and the non-stationary generalized extreme value analysis is applied to estimate the climatic extremes. Independent ENSO influence after removing the IOD trends (ENSO|IOD) on WP are evident over the eastern and central Pacific during December–February (DJF) and March–May (MAM), respectively, which subsequently shifts towards the western Pacific in June–August (JJA) and September–November (SON). The ENSO|PDO impact on WP exhibits similar yet weaker intensity year round compared to ENSO. Extreme WP responses due to the IOD|ENSO include widespread decreases over the tropical and eastern Indian Ocean (IO), with localized increases only over the South China and Philippine (SCP) seas and Bay of Bengal (BOB) during JJA, and the Arabian Sea during SON. Lastly, for the PDO|ENSO, the significant increases in WP are mostly confined to the Pacific, and most prominent in the North Pacific. Composite analysis of different phase combinations of PDO (IOD) with El Niño (La Niña) reveals stronger (weaker) influences year-round. The response patterns in significant wave height (SWH), peak wave period (PWP), sea surface temperatures (SST), and sea level pressure (SLP) helps to explain the seasonal variations in WP.

Influence of climate variability on wind‐sea and swell wave height extreme over the Indo‐Pacific Ocean

Sardana

Intl Journal of Climatology

et al. 2022

In the Indo-Pacific Ocean (IPO), extreme significant wave heights (SWHs) can substantially induce coastal erosion, flooding, and devastating impacts on coastal livelihoods. This study examines the seasonal influence of the El Niño-Southern Oscillation (ENSO), Indian Ocean Dipole (IOD), Southern Annular Mode (SAM), and Pacific North American (PNA) pattern on extreme windwave parameters. The climatic extremes are calculated utilizing ERA5 reanalysis datasets from 1979 to 2019 and a nonstationary generalized extreme value distribution. Significant increases in extreme wind-sea (Hmax) and swell SWH (Hmax Sw ) response to ENSO occur over the northeast North Pacific (NP) during December-February (DJF) and western NP during June-August (JJA).The PNA influence exhibits a similar pattern to ENSO during DJF yet is inactive in JJA. Hmax and Hmax Sw responses to the IOD during September-November (SON) include significant increases over the western Pacific, southern Indian Ocean (IO), and southwest tropical IO, yet decreases over the central tropical IO. The Hmax Sw response to the SAM is larger than that for Hmax over the southern IPO during DJF, which extends toward the eastern Pacific in March-May (MAM). Overall, extreme wind-sea and swell parameter responses are found to be associated with sea level pressure (SLP) and SLP gradients. K E Y W O R D S climate variability, generalized extreme value (GEV) distribution, Indo-Pacific Ocean, wind-sea and swell SWH